CBS and neoplasm: Therefore, this overexpressed endogenous H2S was harnessed for in situ conversion of cuprous oxide (Cu2O) into copper sulfide for activatable PA imaging and photothermal tumor ablation (Figure 4a).[81] It was exemplified that the implementation of S‐adenosyl‐l‐methionine (SAM) as an allosteric CBS activator expedited the in situ reaction between H2S and Cu2O, thus producing significantly strengthened PA imaging signals and photothermal effects for elevating the tumor temperature after 808 nm laser irradiation.